If you haven't used the app called Slice (iOS / Android / Web), here's a great write up by my wife Adelle on her recent experience.
Yay for Slice!
by Adelle Nicolas:
Two weeks ago I had purchased a pair of Corso Como 'Famenka' Flat Nude 6.5 M on Nordstrom.com as a gift to myself for my new job. Nordstrom was in the midst of their Half Yearly sale, so I got a pretty amazing deal on the flats and bought them for under $40!
About a week later, I received a notification on my phone from the Slice app (iOS / Android / Web) that alerted me of a $10 price drop in the shoes I had purchased. The Slice Team also sent me an email about my Nordstrom purchase and included a link to the item I purchased with the new adjusted price, my order number, as well as Nordstrom's customer service number so I could inquire about my refund. I used all the information I was given and talked to Jeff in customer service and I was quickly and kindly refunded the $10 on my credit card. I ended up getting a 50% discount on some very comfortable flats thanks to Slice!
If you have any questions about privacy, you can check out their FAQ. Most importantly, the most asked about question, I've posted here for direct reference.
Does Slice store my password to my email account?
Slice uses a secure protocol called OAuth (oauth.net) to allow for authorization to your Gmail, Yahoo! Mail or Outlook.com account. For these accounts, the authentication happens between you and Gmail, Yahoo or Outlook.com, and we never even see the password you enter for your email accounts. OAuth is used by many popular websites, such as Facebook, Twitter, Netflix and of course, Google, Yahoo! and Microsoft.
For mail providers that do not support OAuth, like AOL, iCloud/MobileMe, Comcast and Cox, we will need to store your email passwords to be able to process your receipts. The passwords will be stored and encrypted in a separate, secure database.
